Review

Congratulations! You've completed the first section of the Programmed Instruction Course. Let's summarize the topics covered in this section:

• Protocol
  • A protocol is "a formal description of message formats and the rules two or more machines must follow to exchange those messages."
  • Protocols let us perform operations on other computers over a network.
  • Many protocols can be in use at once.
  • Protocols should be as specific to one task as possible.

• Standard
  • Standards are protocols that everyone has agreed upon.
  • Standard organizations exist to develop, discuss and enhance protocols.
  • The most important Internet standard organization is the Internet Engineering Task Force (IETF).
  • The most important Internet standard documents are the Requests For Comments (RFCs).

• Protocol Layering
  • Protocols are usually organized by layering them atop one another.
  • Protocol layers should have specific, well-defined functions.
  • The most important protocol layering designs are the 4-layer Department of Defense (DoD) Model, and the 7-layer Open System Interconnect (OSI) Model.

• 4-Layer DoD Model
  • The 4-layer DoD layered protocol model consists of the Process, Host-to-Host, Internet, and Network Access Layers.
  • The DoD Model was developed for the Internet.
  • The core Internet protocols adhere to the DoD Model.

• Encapsulation
  • Encapsulation happens when one protocol's message is embedded into another protocol's message.
  • Protocol layering is implemented through encapsulation.

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Now, click here to proceed into Section 2.